Google has agreed to a $391.5 million settlement with 40 states in connection with an investigation into how the company tracked users’ locations, state attorneys general announced on Monday, calling it the largest multistate privacy settlement in US history.

The investigation by the states, which officials said was spurred by a 2018 Associated Press story, found that Google continued to track people’s location data even after they opted out of such tracking.

“This $391.5 million settlement is a historic win for consumers in an era of increasing reliance on technology. Location data is among the most sensitive and valuable personal information Google collects, and there are so many reasons why a consumer may opt-out of tracking,” Connecticut Attorney-General William Tong said in a statement.

The AP reported that many Google services on Android devices and iPhones store your location data even if you’ve used a privacy setting that says it will prevent Google from doing so.

Storing such data carries privacy risks and has been used by police to determine the location of suspects.

The AP reported in 2018 that the privacy issue with location tracking affected some two billion users of devices that run Google’s Android operating software and hundreds of millions of worldwide iPhone users who rely on Google for maps or searches.

The attorneys-general who investigated Google said a key part of the company’s digital advertising business is location data, which they called the most valuable personal data the company collects.